U.S. Pat. Nos. 4,013,254 and 4,146,140 disclose support structures including hook-equipped brackets and slotted standards for supporting shelves, cabinets, and other furniture units at any of a variety of selected elevations. U.S. Pat. Nos. 4,133,433 and 3,273,847 disclose means for selectively tightening or loosening the hooks of brackets received by slotted uprights, U.S. Pat. No. 4,387,872 discloses a spring-loaded plunger for preventing unintentional detachment of hooks from a slotted standard, and U.S. Pat. No. 2,741,449 discloses a bracket equipped with means for adjusting the bracket, and a shelf which it supports, into horizontal position. Other patents, such as U.S. Pat. Nos. 4,531,698 and 4,134,564, further illustrate the state of the art.
The present invention is concerned with a cantilever arm assembly which may be easily connected and disconnected from a slotted standard and may be positioned at any of a variety of elevations along that standard. Once such a position has been selected, a user actuates locking means which not only prevents unintentional unhooking of the cantilever arm assembly from the standard but also eliminates play or looseness in the interconnection between the parts and, in addition, may be manipulated to adjust the support arm, and any worktop carried by that arm, into true horizontal position.
An important aspect of the assembly is the provision of a vertically-elongated mounting member that is rigidly connected at its upper end to the horizontal support arm (by a rigid internal casting) and is provided at its upper end with a vertical series of hooks adapted to be received and latched into slots provided by a standard or upright. The mounting member has a major proportion of its vertical length extending downwardly below the series of hooks and terminating in a lower end portion spaced above the bottom of the standard. The locking means for preventing accidental upward displacement of the mounting member is located at the lower end of that member and takes the form of a screw having an enlarged head portion engagable with the standard and a pin extension adapted to be received in one of the slots of the standard. Extension of the screw causes the pin to enter a slot and, since a plurality of hooks are provided at the upper end of the mounting member, all of which are received in slots of the standard, rotation of the screw to force its head into tight engagement with the standard results in slight pivotal movement of the mounting member and causes the hooks to pivot into tight frictional engagement with the standard. Such rotation of the screw also pivots the free end of the cantilever arm upwardly, thus permitting a limited range of adjustment for shifting the arm into precise horizontal position.
The secure interlocking relationship between the mounting member of the cantilever arm assembly and the slotted standard is important not only in preventing unintentional release should lifting forces be exerted upon the free end of the arm, as where a worktop secured to the arm, or a cabinet suspended from it, should be lifted or bumped upwardly, but also because it resists disengagement or loosening in response to vibrations, tremors, even earthquakes. While obviously there can be no guarantees against earthquake damage, the cantilever arm assembly of this invention is highly resistant to disengagement from a slotted standard to which it is locked and must be subjected to considerable distortion and damage before any such release can take place.
Other features, advantages, and objects of the invention will become apparent from the specification and drawings.